The invention concerns a wireless telecommunications system with at least one base station and with mobile user terminals according to the global assertion under claim one. In addition to this, the invention is concerned with a base station as well as a mobile user terminal for such a wireless telecommunications system according to the global assertion of one of the coordinate claims.
A wireless telecommunications system with at least one base station and with mobile user terminals is known from U.S. Pat. No. 4,554,668. The system described there contains various base stations which each supply one radio cell, and which each exchange radio signals wit the user terminals found therein. The radio signals are sent and received in varying time slots and frequency slots. Thereby, a given frequency hopping is exchanged, in varying frequency slots, between the frequency slots. The user signals as well as the signaling signals are transferred in this manner, i.e. radio signals are exchanged on the user information channels as well as on the signaling channels within a time grid divided into time slots and in accordance with the given frequency hopping sequence. All of the user terminals described there use a different individual frequency hopping sequence assigned to it. These different individual frequency hopping sequences are produced by a process well known in itself, basically by the process named there in column 3, line 42 ff. for the creation of frequency hopping sequences according to D. V. Sarwattee and M. B. Pursely. This and other processes for the creation frequency hopping sequences are, in themselves, known under the term xe2x80x9cfrequency hopping algorithmxe2x80x9d and serve to make a radio transfer of user signals resistant to interference.
A wireless telecommunications system is known from European patent (EP) 423 715 B1, by which a radio transfer is carried out on user information channels as well as on signaling channels according to a given frequency hopping. The telecommunications system described there contains many equal user terminals which exchange radio signals with each other directly.
A wireless telecommunications system is known from EP 467 600 B1, by which radio signals are exchanged between base stations and mobile user terminals within a time grid divided into time slots, and over a given frequency slot. The radio signals can be signaling signals. A radio transfer through the use of frequency hopping sequences is not described there.
The task of the invention is to improve the wireless telecommunications system mentioned at the outset, in that, first, the signaling channel is suited for the radio transfer of different signaling signals in order to be able to be used for various purposes, especially for initializing and registering and, second, in that an interference resistant radio transfer through the use of frequency hopping sequences is possible. In addition, a base system as well as a mobile user terminal for such a wireless telecommunications system should be proposed.
The task will be accomplished through a wireless telecommunications system in which the base station and the user terminals contain controllers for controlling the frequency slot alternations which produce no frequency hopping for the first portion of the time grid, but rather emit a steady frequency, and which, for at least a further portion of the time grid, produce a pseudorandom frequency hopping according to an iterative process by which the base station sends an input value to the user terminals, by which the controllers of the input value calculate the pseudorandom frequency hopping, and by which the controllers for the registering of the user terminals control the frequency change according to this pseudorandom frequency hopping.
In accordance with this the base station sends an input value to the user terminals after the frequency change for registering the user terminals is controlled, in order to calculate a pseudorandom frequency hopping from it. Thus it is accomplished that a frequency hopping, which is developed on the basis of the input value and does not need to be completely saved, is used already in the transfer of registration signals.
It is especially advantageous if, in the radio transfer on the signaling channel, two different processes for the creation of frequency hopping are used. Thus, a radio transfer of tow different signaling signals on one signaling channel is made possible. This can serve various purposes whereby different, respectively optimally suited, frequency hopping can be used.
It is especially advantageous if the base station and the user terminals with the controllers contain connected means of choosing which ascertain the current time slot and then choose, from the minimum two different processes, that process according to which the controllers control the frequency slot alternations. Thus it is ascertained in a simple manner on the basis of the current time slot, which of the different processes for the creation of frequency hopping sequences should be implemented.
It is also especially advantageous if, first, the base station and the user terminals contain data storage devices in which a predefined frequency hopping is saved which creates the first frequency hopping and, second if, in the initializing signals for the creation of a radio connection, the frequency change according to this predefined frequency hopping is used. Thus it is achieved that the base station as well as any user terminal already know, before the creation of a radio connection, the specific frequency hopping which is to be used in the transferring of initializing signals on the signaling channel. Thus, directly in the creation of the radio connection, the advantage of xe2x80x9cfrequency hoppingxe2x80x9d can be immediately exploited.
Further advantageous uses arise out of the coordinate claims.